hi all. have blogged before here (admittedly, enthusiastically, even ebulliently) on the “digital physics” concept, an enamoring idea (for some!). recently within last few weeks and last year there seems to be substantial new interest and developments even in “semimainstream” physics, and now even the mainstream media is in a semi-lather over close topics. (skeptics will ofc argue the word “semimainstream” sounds something like “semipregnant”!) its hard to keep up! there are many different angles of povs, events, personalities, etc… this post attempts to collect and summarize some of this and bang it all into a semicoherent story (as much as such a thing is possible). some old but evocative buzz/ magic words thrown around about internet expansion into multiple industries come to mind: consolodation/ convergence…

to start, these ideas are now going under the headline of the “holographic universe/ principle”[a2] or “simulated universe/ hypothesis”[a1] concepts. they are interconnected in major and/ or subtle ways.

mentioned Aaronsons recent blog[i3] on subj citing Hossenfelder [i1][i2] in a recent near-throwaway comment in the SE physics chat room “hbar”[a5] to a new accomplished user BenNiehoff (phd KU Leuven working on string theory with 9 papers on arxiv!). hes met a lot of famous physicists at conferences personally eg Susskind, Zee, Green, Schwarz, and Witten and other famous theorists. am trying to recruit him for a guest session in our elite and popular series, but thats another story!

laid out some of the basic concepts/ “pros” of the simulation hypothesis ideas incl/ eg longtime endorsement/ driven pursuit by nobel prize alumnus ‘t Hooft, which thought were not generally very controversial, but the room denizens/ regulars reacted quite adversely-bordering-on-negatively, with some really stinging retorts! guess those big fat shiny nobel prizes and the proverbial “trip to stockholm” just aint what they used to be! Ben expressed his disinclination and looks like they all smelled blood in the water & went in for the kill! 😮 😦

Ah, as usual you have no actual argument to make, I should’ve known. —ACuriousMind [a6]

vzn; do you have any mainstream views? —John Rennie [a7]

😦 😥 😡 that 1st quote was starred by 6ppl! as for the 2nd ofc around these parts those are fighting words! holy cow, really just not feelin the luv … feel free to add your own! (stars, comments, whatever!) nothing left to do but quote it prominently here as an “arrow in my back/ badge of honor/ moment of eternal notorious infamy”!

😳 ok, in a less facetious/ more sober/ reflective moment of nonmania, have to respectfully admit/ concede they definitely have a point. some of their main objections are around poppers falsifiability criteria and they question whether such a hypothesis is even testable, arguing that it seems to make no predictions (but lets also note the irony of someone working/ specializing in string theory levelling this objection)… despite decades of consideration, in other ways these are early days for “simulation hypothesis” (esp wrt actual physics experiments) and seems theres a lot of cacophony on what exactly it means even by proponents/ advocates! but, it also seems likely the opponents are not really aware of all the developments/ facts in the area—but, not that it would change their opinion any! so consider this my own attempt/ effort at some actual argument wrt (“semi-“)mainstream views!

Everyone is entitled to his own opinion, but not his own facts. —Moynihan

was scrounging around for further ammunition, did some further research and found to my surprise an early writeup examining the idea is by Susskind [a4] (1994) who coincidentally JR is a big fan of! only 241current refs to Susskind in the HBar chat room! he seems to be a modern day physics proseletyzer/ pedagogue for laymen esp wrt his very popular “theoretical minimum” books/ lectures.

Susskind is one of the giants of modern theoretical physics, with a lifetime of achievements behind him. —JohnRennie

so it was an interesting mini engagement, have to momentarily retreat/ retrench/ regroup/ revamp to a safe place! at least can be sure nobodys gonna write a hostile comment on this blog eh? 😐

one of the biggest experiments in this area is work at Fermilab by Hogan/ Cho, the latter calling the 7-figure project “shoestring”.[b] acc to wired[c12] this project was actually based on real anomalous observed data although it doesnt seem to be cited much or at all in their writeups.

Inspiration for the holometer came from such a noise picked up by an experiment called GEO600. Designed to detect gravity waves — ripples in space-time caused by things like colliding black holes — the machine is a laser interferometer like the holometer will be, yet has arms 15 times longer and a laser designed to detect lower frequencies (to be sensitive to gravity waves, if they exist).

Experimental physicist Hartmut Grote, of the Max Planck Institute in Germany, said he and his colleagues at GEO600 have been unable to pinpoint the source.

“In the past, [Hogan] became a little bit driven, even excited for some time, that this noise could be a result of the holographic principle,” Grote said.

admit some cognitive dissonance even myself on all this! it seems a bit hard to follow the direction/ focus of this project, it originally started out as involving highly precise atomic clocks, and later writeups it is talking about detecting very high frequency gravity waves! “reading between the lines” it seems maybe the architects needed to respond to current scientific trends to hustle to keep it in business/ alive!

the basic machine is called a “holometer” which is designed to measure very fine jiggles in spacetime fabric so to speak. popsci articles eg [c5] talk about hogans ideas of a “pixellated universe”. hogan has documented but “unpublished” ideas on the subj.[b10] his writeup in Phys Rev Letters [b6] seems like it is a “different story,” highly sanitized scientific writing without almost any ref to all the wild popsci writings on the subject. the (popsci) press had something of a field day describing this experiment to various degrees of seriousness.[c] apparently the researchers have a very colorful personality “semi off record” when being interviewed by writers/ reporters…?

however, amidst all the buzz, theres already a null result reported. so the question is settled and skeptics/ naysayers win right? 😐 🙄

➡ 💡 ❗ 😮 but wait! stop the presses! recently (Jan 2017) there was an announcement of “substantial evidence of a holographic universe” by a team analyzing the cosmic microwave background! [a3]

A UK, Canadian and Italian study has provided what researchers believe is the first observational evidence that our universe could be a vast and complex hologram. Theoretical physicists and astrophysicists, investigating irregularities in the cosmic microwave background (the ‘afterglow’ of the Big Bang), have found there is substantial evidence supporting a holographic explanation of the universe — in fact, as much as there is for the traditional explanation of these irregularities using the theory of cosmic inflation.

another mostly theoretical direction/ angle is a paper published 2012 by Beane et al focuses on looking at anomalies in cosmic rays.[d] this theoretical work does not seem to be being pursued on an experimental level “yet” but it also led to some major popsci media ripples incl even the NYT.

then there are some ideas being proposed by a Viennese group in 2014.[e] this work theoretically links up the Maldacena AdS-CFT correspondence to “non exotic” or “non-toy” spacetimes not unlike our own. staggeringly, more than a thousand papers have been published on the AdS-CFT correspondence since its inception exactly 2 decades ago (1997).

a key researcher/ advocate of the theory but more from the philosophy background is Bostrom who has a new book out on AI, and there are other scientists semi seriously discussing the topic.[i]

but theres a kind of big lumbering elephant in the room, or maybe a bull in a china shop—the popsci press and writers are having a bit of a field day with all the Matrix connections. to me its a bit of a pity because theres a lot of serious scientific/ physics inquiry but it tends to get distorted in the media noise. so again the popsci reverberations take on a kind of life of their own with even New Yorker and Atlantic jumping onto the bandwagon.[f]

and not sure it was really much help that media darling/ wonder boy Elon Musk endorsed the idea, definite mixed feelings on that one! [g] (did you not recall Musk was the inspiration for Iron Man and is dating Depp exwife Heard? oh and hes going to go to Mars? oh and also in his copious spare time is working on a human-machine merge and doing cameos in latest silly hollywood comedies? oh and forgot the hyperloop oh and not to mention that little car company startup Tesla! and not the only mogul-iron man connection … its a strangely small world that way…) it seemed to really increased its exposure but also, nearly in equal and opposite measures, the hype/ skepticism/ pushback. this reminds me of how Musk has started to talk a lot about/ move into AI and abruptly get in the game (an instant gamechanger) only in the last few years, causing some recoil/ critics/ skeptics. (modern day Daedalus?) and much of this is all so nicely laid out in this recent great article by maureen dowd, “Elon Musks billion-dollar crusade to stop the AI apocalypse” in—where else? dont cringe from the irony, too much—vanity fair…

a lot of media airplay was given to the Neil deGrasse Tyson mtg involving various physics heavyweights in april 2016 where they debated the topic at an Asimov memorial panel.[h]

there are a few scattered stackexchange questions on the ideas, found these & presume there are various others, will keep my eye out for more.[j]

⭐ 😎 💡 ❗ ❓ so anyway, its a sort of free-for-all or near-melee in this area at the moment, and not easy to separate signal from the noise (the naysayers might argue that theres no signal at all in the noise!) but for someone like me, its very cool bordering on exciting to see theoretical research/ advances and glimmers of serious/ substantial empirical/ experimental testing of this at-times highly abstract/ theoretical idea thats been floating around for decades and has some relation/ natural affinity with computer science.

its neat that its crosscutting/ interdisciplinary from so-called “shoestring/ tabletop” physics to astronomy/ cosmology (cosmic microwave background) and cosmic rays, even maybe relating to the newly discovered gravitational waves. it looks like a lot of different researchers may be in on the “action” some day… or not. physics and computer science maybe havent gotten entirely married but these days if not its definitely at least a very Long Term Relationship between Significant Others…

& as for all the pushback/ resistance in the physics chat room Hbar, maybe its like that old expr, keep your friends close, and your enemies closer.™

except, one last wrinkle… now what to do with frenemies? ah, maybe have got it— keep em in cyberspace! 😛 😈